1. Field of the Invention
The invention disclosed broadly relates to telecommunications systems and more particularly relates to mobility applications.
2. Background Information
In 1982, the global system for mobile communications (GSM) was established in Europe, to provide a cellular mobile radio system. The primary function of the GSM is to provide a full roaming mobile telephone service. The GSM protocol has been selected for use around the world for digital cellular telephone service. The principles of operation of the existing GSM digital cellular telephone system is described in the following references: Balston, D. M., "Pan-European Cellular Radio" IEEE , Electrical and Communications Journal, No. 1, pp. 7-13, 1989.
Goodman, D. J., "Second Generation Wireless Information Networks", IEEE Transactions on Vehicular Technology, VT-40, May 1991, pp. 366-374.
Pautet, M. B., and Monly, M., "GSM Protocol Architecture: Radio Subsystem Signalling", IEEE Vehicular Technology Conference, May 1991, pp. 326-332.
A cellular mobile radio system includes a variety of elements. There are mobile stations (cellular telephones). Each cell of the cellular network contains a base station which transmit calls to and receive calls from the mobile stations using radio. There are base station controllers (BSC) which control a cluster of base stations. There are mobile switching centers (MSC) which route calls between base stations, other mobile switching centers and the public switch telephone network. Each MSC is associated with a home location register (HLR) and a visitor location register (VLR). The HLR stores a mobile station profile for each mobile station in the network. When a mobile station is operated, the mobile station profile in the HLR corresponding to that mobile station is sent over a data network to a VLR associated with the MSC serving the cell in which the mobile station is located. Several data network messages are required to complete each transaction. A transaction occurs every time a call is placed or received by a mobile station, as well as every time a mobile station is switched on. A problem in the prior art is that the call traffic capacity of the system is limited by the message handling capacity of the data network coupling the VLRs with the home location register. The message handling capacity of the data network can be increased by increasing the number of HLRs or by increasing the throughput of the data network, but this requires investment in new or additional equipment.